Hello CESAR VASQUEZ2,
Welcome to Microsoft Community.
You may not be able to do this on the default Windows system, because .scr files do not come with the system's own file format.
The most common way to convert the format is to directly change the suffix of the file, but this operation can cause problems such as file corruption, unreadable, etc.
To safely convert Notepad text files (.txt) to .scr files, you will need to use specific software or tools to do the conversion, but unfortunately, we are unable to recommend it to you.
What we can remind you is to make sure you understand the structure of the terrain coordinates in the TXT file and that they are written in the correct format.
Best regards,
Mitchell - | Microsoft community support expert from MSFT